In most cases when surgery has been performed on a patient to suture tissue around a small pit in a digestive tract or other hollow organ, including perforations in lesions caused by cancer or the like, accidental piercings (punctures and other surgical wounds) occurring during treatment, and perforations formed for performing endoscopic gall-bladder surgery through the patient's stomach, the surgery has conventionally involved major procedures such as abdominal incisions. Recently, however, less-invasive surgical methods involving transoral or transanal endoscopic procedures have been proposed, and practical applications of these methods are currently being researched and developed.
In the following description, the portion of a device or hollow organ that is the farthest inside the patient's body from a natural orifice, such as the mouth or anus, will be referred to as the “leading (or forward) end” or “front part” or “far end,” while the portion of the device or duct closest to the outside of the body will be referred to as the “rear end” or “rear part” or “near end.”
One example of a conventional transoral or transanal endoscopic instrument for small-pit closure in hollow organs is the suturing device 301 shown in FIGS. 30 through 33. The suturing device 301 sutures tissue by using a suture unit 333 that includes a suture thread 334, to whose respective ends are attached a first anchor 336 and a second anchor 337. The suturing device 301 also includes: a hollow tip (needle) 304 that houses the anchors 336 and 337; a wire 305 that has a front end that is inserted into the tip 304 for ejecting the first and second anchors 336 and 337 out of the tip 304; a flexible tube 307 that has a leading end integrally connected to the rear end of the tip 304 and through which the wire 305 is inserted and is capable of advancing and retracting in the axial direction of the flexible tube 307; a second sheath 306 that is inserted into the flexible tube 307 and is capable of advancing and retracting in the axial direction together with the wire 305; an abutting member 310 mounted on the wire 305 for maintaining a fixed relative positional relationship between the wire 305 and second sheath 306; a connecting tube 311 provided on the flexible tube 307 or the tip 304 for restricting the forward movement of the second sheath 306; and an operating part 303 provided on the rear end of the wire 305 and second sheath 306 for operating the wire 305 and second sheath 306. When the wire 305 is moved forward while the abutting member 310 holds the relative positions of the wire 305 and second sheath 306 constant, the wire 305 ejects only the first anchor 336 out of the tip 304 after the connecting tube 311 restricts the forward movement of the second sheath 306 (refer to FIGS. 1-11 in Patent Document 1, for example).
A laparoscopic surgical instrument for small-pit closure can also be readily applied when using transoral or transanal endoscopy in small-pit closure surgery of hollow organs. A typical laparoscopic suture/closure instrument includes a cannula 412 that includes: a connecting rod 420 that has an actuating mechanism for advancing or retracting in the axial direction of the cannula 412; a needle-suture complex 422 that is attached to the far end of the connecting rod 420 and that has a pair of needles 426a and 426b that, in an operative configuration, extend outward from the far end of the cannula 412 in opposite directions to each other to positions beyond the periphery of the perforated site, and a suture thread 428 that extends between the pair of needles; and a needle-trap mechanism 432 for engaging and locking with the needles 426a and 426b deployed in the operative configuration. A needle-trap mechanism 432 operates to draw needles 426a and 426b into the cannula 412, drawing the suture thread 428 that extends between the needles 426a and 426b from the perforated site and forming a closure in the perforated site (refer to FIGS. 1-8 of Patent Document 2, for example).